1. Field of the Invention
The present invention relates to a sliding device for a storage case, and, more particularly, to a sliding device which can slide smoothly when mounted inside a storage case, such as a refrigerator, in a humid and cold (freezing) environment.
2. Description of Related Art
To promote smooth movement backward and forward of a heavy storage container containing a storage case with goods therein, sliding devices are provided on both outer side surfaces of the storage container and both inner side surfaces of the storage case.
Such sliding devices typically include a fixed rail, a movable rail, a plurality of balls, and a supporting means for the balls mounted on an inner side surface of the storage case. The fixed rail extends over its full length in the sliding direction of the storage container. The movable rail is mounted to an outer side surface of the storage container in alignment with the fixed rail and slides along the fixed rail. The plurality of balls are located between the fixed rail and the movable rail.
The fixed rail and the movable rail are made from roll formed metal plates. The rails are formed with concave guiding grooves for receiving the balls therein. The balls roll along the guiding grooves while closely contacting the grooves.
When this type of sliding device is used in a storage case for storing foods, the metal rails and balls may oxidize, i.e., rust, since the component parts of the sliding device are exposed to moisture. Thus, the rolling motion of the balls is eventually impaired and it becomes troublesome to open or shut the storage container. That is, if the guiding grooves and the small rolling balls become rusty, the sliding motion of the storage container is impaired and the life of the sliding device is shortened.
Further, when this type of sliding device is used in a storage case for a refrigerator or the like which is kept humid and cold, i.e., at a temperature below the freezing point, moisture is condensed and frozen on the rails or the balls, thereby impeding the sliding motion of the storage container.
Finally, because the fixed rail and the movable rail are made by roll formed metal plates, the manufacturing cost of these rails is high.
The present invention concerns a sliding device for a storage case which is constructed to solve the problems discussed above.
It is an object of the present invention to provide a sliding device for a storage case which does not rust but which provides a smooth sliding motion even when the storage case is kept humid and cold (below the freezing point) and granular ice is formed on rails.
It is another object of the present invention to provide a sliding device for a storage case which is durable and can be manufactured more easily and cheaply than conventional devices used for the same purposes.
In accordance with the invention, a sliding device is provided for providing sliding backward and forward movement of a drawer-type storage container relative to a storage case, the storage container being slidably mounted inside the storage case, and the sliding device comprising: a first plurality of rollers; a second plurality of rollers; a fixed rail fixedly mounted to an inner side surface of the storage case and including a roller coupling portion rollably receiving the first plurality of rollers; a movable rail fixedly mounted to an outer side surface of the storage container and including a roller coupling portion rollably received in the second plurality of rollers; and a middle rail slidably mounted between the fixed rail and the movable rail for providing a coupling relationship therebetween and for guiding the rolling motion of the first and second plurality of rollers, such that the movable rail and the storage container slide together by means of a rolling motion of the second plurality of rollers along the middle rail, and the middle rail slides along the fixed rail by means of a rolling motion of the first plurality of rollers.
Preferably, the middle rail further comprises an upper rail portion, including an upper channel for receiving the roller coupling portion of the movable rail therein and for guiding the sliding motion of the movable rail, a lower rail portion including a lower channel for receiving the roller coupling portion of the fixed rail therein and for guiding the sliding motion of the middle rail, and a partition rail portion integrally connecting the upper rail portion and the lower rail portion while partitioning the upper channel from the lower channel, and the fixed rail includes guiding space receiving the upper rail portion and the movable rail includes a guiding space for receiving the lower rail portion.
Advantageously, the upper rail portion of the middle rail opens toward the roller coupling portion of the movable rail, and the lower rail portion of the middle rail opens toward the roller coupling portion of the fixed rail.
Preferably, first movement restricting means are located between the fixed rail and the middle rail for restricting the movement of the middle rail, and second movement restriction means are located between the middle rail and the movable rail for restricting the movement of the movable rail.
Advantageously, the first and second movement restricting means each include hooking members and respective openings for receiving the hooking members therein.
Preferably, the hooking members protrude upwardly from the upper end surface of the middle rail and downwardly from the lower end surface of the middle rail, and the openings extend longitudinally of the fixed rail and at the movable rail, respectively.
Advantageously, a plurality of slots are formed in the roller coupling portions of the fixed rail and movable rail, respectively, such that the first plurality of rollers and the second plurality of rollers extend through the slots and undergo rolling motion in contact with the corresponding partition rail portion.
Preferably, the partition rail portion includes guiding grooves extending of the partition rail portion for guiding the rolling motion of the first and second plurality of rollers.
Advantageously, the invention further comprises a first roller supporting member within which the first plurality of rollers are disposed in series and a second roller supporting member within which the second plurality of rollers are disposed in series, the first roller supporting member being disposed in the roller coupling portion of the fixed rail and the second roller supporting member being disposed in the roller coupling portion of the movable rail.
Preferably, the movable rail is comprised of an injection molded plastic, the fixed rail is comprised of an injection molded plastic, the middle rail is comprised of an injection molded plastic, and the rollers are comprised of an injection molded plastic.
Further features and advantages of the present invention will be set forth in, or apparent from, the detailed description of preferred embodiments thereof which follows.